A vehicle control device can control an operation of a vehicle by performing a control operation with an arithmetic logic unit of a microcomputer or a central processing unit (CPU). Since the arithmetic logic unit generally needs to be supplied with a constant voltage, the vehicle control device is provided with a constant voltage generation circuit. The constant voltage generation circuit generally receives a supply of a higher voltage from a power source such as a battery used by the vehicle control device, and converts this voltage into a specified constant voltage to supply to a load circuit, such as the arithmetic logic unit.
PTL 1 below discloses a technology relating to a power supply switching circuit that switches a first and second power supplies. In PTL 1, a voltage of the first power supply and a voltage of the second power supply are compared, and a transistor provided between a load and a power supply having a higher voltage is turned ON (refer to Abstract).